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PURPOSE OF THE STUDY The orthopaedic community has unanimously adopted the view that ultra high molecular weight polyethylene (UHMWPE) wear particles are a very frequent cause of aseptic implant loosening. Some studies have tried to provide objective evidence for this. We have found descriptions of particle distribution or morphology, but no report that would objectively correlate the number of particles in zones surrounding an implant with the extent of damage to these zones. The aim of this study was to develop a method allowing us to evaluate a number of samples with polyethylene abrasive wear large enough to find association between the extent of damage around a THA and the number of biologically active UHMWPE wear particles, 0.1 to 10 μm in size . MATERIAL AND METHODS In 28 patients undergoing revision total hip arthroplasty (THA) at the 1st Orthopaedic Clinic, 1st Faculty of Medicine, Charles University, we took samples of typical osteoaggressive granuloma from defined zones around the implant; the zones corresponded to those described by Gruen and DeLee. The extent of tissue damage in each zone was evaluated on the basis of pre-operative radiographs and by the extent of osteolysis and damage to soft tissues actually observed during revision THA. The volume of wear particles in each zone was assessed by the IRc method developed by us; this is based on a quantitative evaluation of infrared spectra. To verify the methodology, a comparison between tissue damage and the number of particles in each zone was made in three randomly selected patients. RESULTS We introduced a method of detailed orthopaedic evaluation which enabled us to categorize zones around a revised THA according to the extent of damaged tissue. As a result, a series of zones ranked by the extent of damaged tissue, or an "orthopaedist?s statement" (OS), was obtained. At the same time we adopted a method, based on infrared spectroscopy and termed IRc, by which the number of particles in the samples of damaged tissues and osteoaggressive granulomas collected from the area around a revised THA was determined. The results of evaluation were presented as numerical data that, in a defined way, were converted into a series of zones ranked according to the number of wear particles, i.e., the "result of measurement" (RM). In this study we verified the methods described above and made a comparison of OSs and RMs for three randomly selected patients. The very good agreement found confirmed the reliability of both methods which will soon be used to evaluate a group of patients large enough to provide statistically significant results. DISCUSSION The IRc method determines a total volume of UHMWPE wear particles, 0.1 to 10 μm in size, which are generally considered to be most biologically active. This study suggests that the distribution of particles around a THA is uneven and that relation between tissue damage and the number of wear particles in individual zones surrounding a THA does exist. The major conclusion from the orthopaedic point of view is a confirmation of the assumption that UHMWPE wear particles are one of the chief causes of THA failure. Although this fact is generally accepted, studies correlating the number of particles with tissue damage and osteolysis in individual zones are very scarce. CONCLUSIONS The quick and simple IRc method offers a possibility to quantify polyethylene wear particles in soft tissues. The number of 0.1 to 10 μm wear polyethylene particles correlated with pre-operative radiographic findings and orthopaedic evaluation of revision THAs in three randomly selected patients. The confirmed correlation between the extent of tissue damage in individual zones surrounding a THA and the volume of wear particles detected in these zones supports the view that UHMWPE wear particles are one of the main causes of THA failure.
- MeSH
- financování organizované MeSH
- granulom etiologie MeSH
- kyčelní kloub patologie MeSH
- kyčelní protézy škodlivé účinky MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- náhrada kyčelního kloubu MeSH
- polyethylen terapeutické užití MeSH
- reoperace MeSH
- selhání protézy MeSH
- spektrofotometrie infračervená využití MeSH
- spektrometrie rentgenová emisní MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- hodnotící studie MeSH
Information on the distribution of UHMWPE wear particles around joint replacements is essential for the understanding of aseptic loosening of implants.
The paper addresses the wear particles released from commercially available "low-metallic" automotive brake pads subjected to brake dynamometer tests. Particle size distribution was measured in situ and the generated particles were collected. The collected fractions and the original bulk material were analyzed using several chemical and microscopic techniques. The experiments demonstrated that airborne wear particles with sizes between 10 nm and 20 μm were released into the air. The numbers of nanoparticles (< 100 nm) were by three orders of magnitude larger when compared to the microparticles. A significant release of nanoparticles was measured when the average temperature of the rotor reached 300°C, the combustion initiation temperature of organics present in brakes. In contrast to particle size distribution data, the microscopic analysis revealed the presence of nanoparticles, mostly in the form of agglomerates, in all captured fractions. The majority of elements present in the bulk material were also detected in the ultra-fine fraction of the wear particles.
Ultra-high molecular weight polyethylene (UHMWPE) wear particles play a significant role in failures of total joint replacements (TJRs). In this work, we investigated the distribution of these wear particles in periprosthetic tissues obtained from nine revisions of hip TJR. In the first step, all periprosthetic tissues were combined and mechanically separated into granuloma tissue (containing hard granules visible to the naked eye) and surrounding tissue (without visible granules). In the second step, the tissues were hydrolyzed by protease from Streptomyces griseus and granules were separated by filtration; this divided the sample into four groups: (i) lyzate and (ii) non-degraded large granules from the granuloma tissue plus (iii) lyzate and (iv) non-degraded small granules from the surrounding tissue. In the third step, the large as well as small granules were hydrolyzed by collagenase from Clostridium histolyticum. In the last step, the UHMWPE wear particles from all four groups were purified by HNO3 digestion and weighed. The purity of the isolated particles was verified by scanning electron microscopy, infrared spectroscopy and energy-dispersive X-ray analysis. Of the total amount of polyethylene particles in the whole granuloma tissue, 72% of particles in the size range 0.1-10 microm and 68% of those larger than 10 microm were found in granules. Therefore, the formation of granules significantly lowers the effective amount of wear particles available for interaction with reactive cells and seems to be a natural defense mechanism.
- MeSH
- granulom patologie MeSH
- kosti a kostní tkáň metabolismus patologie MeSH
- kyčelní kloub metabolismus patologie MeSH
- kyčelní protézy MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- náhrada kyčelního kloubu MeSH
- polyethyleny chemie MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- spektrometrie rentgenová emisní MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PURPOSE OF THE STUDY The aim of the study was to evaluate in vivo and compare, in terms of the quality and number of ultra high-molecular polyethylene (UHMWPE) wear particles, total knee replacements of identical construction differing only in the material used for femoral component production, i.e., CoCrMo alloy or ZrO2 ceramics. MATERIAL AND METHODS Samples of peri-prosthetic granuloma tissue were collected in two patients with total knee replacement suffering from implant migration, who were matched in relevant characteristics. The primary knee replacement in Patient 1 with a CoCrMo femoral component was done 7.2 years and in Patient 2 with a ZrO2 implant 6.8 years before this assessment. The polyethylene wear-induced granuloma was analysed by the MORF method enabling us to assess the shape and size of wear debris and the IRc method for assessment of particle concentration. RESULTS In the granuloma tissue samples of Patient 1, on the average, particles were 0.30 mm in size and their relative volume was 0.19. In the Patient 2 tissue samples, the average size of particles was 0.33 mm and their relative volume was 0.26. There was no significant difference in either particle morphology or their concentration in the granuloma tissue between the two patients. DISCUSSION One of the options of how to reduce the production of polyethylene wear particles is to improve the tribological properties of contacting surfaces in total knee replacement by substituting a cobalt-chrome femoral component with a zirconia ceramic femoral component. The previous in vitro testing carried out with a mechanical simulator under conditions approaching a real weight-bearing in the human body did show a nearly three-fold decrease in the number of UHMWPE wear particles in zirconia components. The evaluation of granuloma tissue induced by the activity of a real prosthetic joint for nearly seven years, however, did not reveal any great difference in either quality or quantity of polyethylene debris between the two replacements. The difference of surface roughness between CoCrMo (Ra = 0.05) and ZrO2 (Ra = 0.02) components did not play any role in in vivo conditions. CONCLUSIONS In accordance with a previous clinical study, this evaluation of the quality and quantity of UHMWPE wear particles produced by a ceramic femoral component in vivo failed to demonstrate any advantage of zirconia ceramic components over the cobalt-chrome femoral components so far used.
- MeSH
- analýza selhání vybavení MeSH
- keramika MeSH
- lidé středního věku MeSH
- lidé MeSH
- polyethyleny MeSH
- protézy kolene MeSH
- reakce na cizí těleso etiologie patologie MeSH
- selhání protézy MeSH
- senioři MeSH
- slitiny chromu MeSH
- totální endoprotéza kolene MeSH
- velikost částic MeSH
- zirkonium MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- srovnávací studie MeSH
Binding of five human plasma proteins (IgG, serum albumin, α(1)-acid glycoprotein, holo-transferrin, α(1)-antitrypsin) to ultra high molecular weight polyethylene wear particles (0.1-10 μm) isolated from hip periprosthetic tissues was studied in vitro. All tested plasma proteins were bound to wear particles in a similar way indicating irreversible binding. Analogous interaction was found also between GUR 4120 particles (diameter ∼250 μm) and two tested plasma proteins (human serum albumin and α(1)-acid glycoprotein). The binding was not affected by pH of a buffer or the isoelectric point of bound proteins; thus it was apparently of clearly hydrophobic nature. We hypothesize that the binding causes some unfolding of the bound proteins, thus exposing new determinants with which sensitive cells may react. This could be a mechanism by which polyethylene wear particles trigger, for example, macrophages activity and thence initiate aseptic inflammation and cause the failure of total joint replacements. Results can contribute to the choice of a convenient construction type of prostheses.
- MeSH
- aktivace lymfocytů MeSH
- aktivace makrofágů MeSH
- koncentrace vodíkových iontů MeSH
- krevní proteiny metabolismus MeSH
- kyčelní protézy MeSH
- lidé MeSH
- polyethyleny chemie metabolismus MeSH
- pufry MeSH
- selhání protézy MeSH
- testování materiálů MeSH
- vazba proteinů MeSH
- velikost částic MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
New colorimetric methods are described for determination of sub-milligram amounts of ultra-high molecular weight polyethylene (UHMWPE) wear particles. These methods are based on the irreversible binding of the fluorescein-conjugated bovine serum albumin or the hydrophobic dye Oil Red O to wear particles. UHMWPE particles bind both substances from their solutions and thus decrease the absorbance of these solutions. The decrease is linearly dependent on the amount of added wear particles in the sub-milligram range suitable for practical use. The newly developed method offers improved accuracy and precision compared to Fourier transformed infrared spectroscopy (Slouf M, et al. Quantification of UHMWPE wear in periprosthetic tissues of hip arthoplasty: description of a new method based on IR and comparison with radiographic appearance. Wear 2008;265:674-684.).
The most critical factor in the development of periprosthetic osteolysis (OL) in total hip arthroplasty (THA) is the biological reaction to wear debris. This reaction is dependent, in part, on the size and concentration of particles, which are determined predominantly by the polyethylene (PE) wear rate. This implies that the risk for developing OL and prosthesis failure can be estimated from wear measurements. We developed a computational algorithm for calculating the total number of PE particles for volumetric wear when particle size and distribution are known. We found that: (i) total number of PE wear particles decreases up to 5 orders of magnitude if the average size of particles increases and the total volumetric wear remains constant; (ii) total amount of PE wear particles decreases up to 4 orders of magnitude if the width of the distribution increases and total volumetric wear remains constant; (iii) for the same volumetric wear, the number of particles significantly decreases/increases with the increase/decrease in their average size and range. These findings suggest that the risk for the development of OL in THA cannot be simply estimated from the volumetric wear alone.
- MeSH
- algoritmy MeSH
- lidé MeSH
- náhrada kyčelního kloubu škodlivé účinky MeSH
- osteolýza etiologie MeSH
- polyethyleny chemie MeSH
- selhání protézy MeSH
- velikost částic MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
